I wasn’t able to locate the service manual for this. I did find a site selling parts with pictures. From there, I could see that the hammer weights actually have imprinting on them. Inspect the ones you need to replace for similar markings.
White key hammers:[br]
+
WA, WB, WC, WD
Black key hammers
BA, BB, BC, BD
[image|2361509]
+
+
If yours lack imprints, there are subtle differences in the metal shapes that can be used as a guide. https://syntaur.com/keyboard.php?keyboard=2439
I wasn’t able to locate the service manual for this. I did find a site selling parts with pictures. From there, I could see that the hammer weights actually have imprinting on them. Inspect the ones you need to replace for similar markings.
White key hammers:[br]
WA, WB, WC, WD
Black key hammers
BA, BB, BC, BD
[image|2361509]